1. Field of the Invention
The present disclosure generally relates to the identification and treatment of wellbore formation fluid zones and, more particularly, to real-time identification of water zones in wells being drilled in an underbalanced state and the treatment of such water zones.
2. Background
In underbalanced drilling, the pressure of the wellbore annulus is typically less than the pressure of the geologic formation in which the wellbore is drilled. As such, in underbalanced drilling, formation fluids move into the wellbore and are recovered in real-time along with drilling fluids, such as mud, utilized to drill the wellbore. To the extent these recovered fluids are analyzed, they may be analyzed to identify and gather insight on hydrocarbon bearing zones so as to subsequently assist in facilities design and in the placement of a completion string. The completion string may include perforators, filter assemblies, flow control valves, downhole permanent gauges, hangers, packers, crossover assemblies, completion tools, and the like.
Once the completion string has been placed in a drilled wellbore, various techniques exist for addressing migration of water into the production tubing from water zones in the formation. It is well known that excessive water production from a formation during hydrocarbon recovery can greatly affect the economic life of a producing well. A variety of gelants, foams, precipitates, or other chemicals (collectively referred to as “conformance fluids”) are used by the industry to plug these water zones in order to control water production. The conformance fluids are selectively placed by injection equipment or some other selectivity mechanism to ensure that oil or hydrocarbon-bearing zones are not damaged. This injection equipment or these selectivity mechanisms may be utilized in conjunction with the completion string or may require that the completion string be tripped out of the wellbore while the water zones are addressed.
In some instances, it may be beneficial to manage the movement of water into the wellbore prior to placing the completion string. For example, since additional costs are associated with safely storing or disposing of water recovered from the geologic formation, it may be desirable to plug the water zones as early in the wellbore operations as possible in order to minimize or manage these additional costs.